This invention is in the field of scanning systems of the type where light is directed upon a medium, such as an envelope containing a mailing address, and reflected from a surface so that there is irregular reflectance. Alternatively, light may be directed towards a film with light passing through the transparent portions thereof to obtain an image through irregular transmission. The scanning system may be used with a processor wherein a determination is made as to the image or text that is contained on or within the medium. An example of such a scanning system is one in which light is reflected from a document containing text and reflected onto a plurality of light transducers, such as photocells or charge couple devices. Each light transduced receives light reflected from an individual picture element (pixel) being scanned at a given instant. Analog signals are received from the individual transducers and are converted to digital signals before being sent to a logic processor that performs a series of steps to determine whether the signals represent black (no light reflected) or white (light reflected) pixels. By processing all the signals, the text on the document can be determined by the processor.
Certain prior art scanning systems used a retina consisting of a two dimensional distribution of photocells and would simultaneously receive the entire image of a character to be recognized. This normally required a static system in which the document would be placed under the retina so as to assure appropriate alignment between the character to be identified and the retina. These systems had the disadvantage of being too slow. More recently, dynamic scanning systems have been developed wherein documents may be conveyed past a plurality of linearly aligned photocells forming a single row. The single row of photocells were usually divided into several sections in order to overcome time response limitations of the photocells. For example, a 512 photocell linear array would be divided into eight units of 64 photocells each. Doing so resulted in two disadvantages. The first disadvantage had to do with the high number of adjustments or calibrations that were required for the many amplifiers in such a system. In addition, a program had to be established in the processor receiving the output of the scanning system to orient the signals in their proper sequence because of the original division into eight groups of 64. The information received from the 512 photocells by the processor would be in the sequence of the signal from the first photocell being received, the top photocell, then the signal would be received from 65th photocell, then the 129th, 193rd, 257th, 321st, 385th, 449th, 2nd, 66th, 130th, 194th and so forth, these numbers representing the photocells from the top of this array, No. 1, to the bottom of the array, number 512. The processor was required to resequence these numbers into the proper order 1, 2, 3, 4 . . . 512 in order to process the information contianed by these signals and identify the characters being presented. This obviously took capacity of the processor and was time consuming.